High frequency generator



Jan. 7, 1936. H N 2,026,892

HIGH FREQUENCY GENERATOR Filed Nov. 11, 1951 ir-ii-"f i," 0, IUUUUUUUU n.

ZMPL/F/ER. Q I 27 Humg; AMPLIFIER.

INVENTORT RALPH M. HE/NTZ. BY J g AMPLIFIER. ATTORNEY Patented Jan. 7, 1936 HIGH FREQUENCY GENERATOR Ralph M. Heints,

Heintz & Kaufman, Ltd., San

Palo Alto, Calif., asslgnor to Francisco, Calif.,

a corporation of Nevada Application November 11, 1931, Serial No. 574,280

2 Claims.

My invention relates to high frequency generators or frequency multipliers.

Among the objects of my invention are: To provide a high frequency generator adapted to 5 produce radio signals; to provide a constant frequency generator; to provide a frequency multiplier capable, with proper design, of giving frequency multiplication of one thousand or more; to provide a generator of radio signals wherewith the current used may be generated and amplified at low frequency, and multiplied to the required high frequency in a single stage immediately preceding the output tube; and to provide a generator which may be tuning-fork driven and wherein the frequency multiplication secured is a definitely known function of the construction of the apparatus. A further object of my invention is to provide a means of utilizing both primary and secondary electron emission to give additional power in the output circuit of the generator.

Other objects of my invention will be apparent or will be specifically pointed out in the description forming a part of this specification, but I do not limit myself to the embodiment of my invention herein described, as various forms may be adopted within the scope of the claims.

Referring to the drawing:

Figure 1 is a representation, partly in section,

and partly schematic, of. the high frequency generator of this invention. I

Figure 2 is a front elevation of the foraminated anode utilized-in connection with my invention, two arrangements of the foraminations being indicated in this figure.

Figure 3 is a schematic diagram showing the arrangements of the low frequency circuits utilized in the frequency multiplier or generator.

A. H. Brolly, in an application for United States 4 patent, Serial No. 574,292, filed November 1, 1931, has shown a method of utilizing a cathode ray device to provide frequency multiplication for generating a high frequency scanning current for use in television. The present invention is a modification of. the Brolly device primarily adapted for use as a driver for producing a carrier oscillation for radio communication. The instant invention differs from the Brolly arrangement in that it is capable of producing higher power, is adapted for use on higher voltages, and is, furthermore, adapted to produce extremely constant frequencies, whereas the Broliy arrangement varies slightly in frequency through the input or low frequency cycle, in a manner which is advantageous for the work for which it was designed, but which seriously limits its usefulness as a producer of carrier current.

Considered broadly, my invention comprises means for establishing a rotating electromagnetic or electrostatic field of a relatively low frequency, 5 and means for directing a beam of cathode rays through this field in such a manner that the beam will be deflected in a closed two-dimensional path, preferably substantially circular. An anode is positioned to intercept the beam of cathode rays, and a second anode, having alternate bars and spaces, is positioned in front of the first mentioned anode in such a manner that the deflected beam will alternately be intercepted by the bars and passed through the spaces to reach the first anode. The two anodes are connected through an impedance element, across which is developed a voltage which may be used to drive an amplifier tube. There is also preferably provided a pair of secondary anodes positioned to receive secondary electrons liberated by bombardment from the two primary anodes. These secondary anodes are connected to their respective primary anodes by a circuit containing impedance elements across which voltages are generated which are substantially in phase with that developed between the two primary anodes, and the output which drives the amplifier tub'e preferably is arranged to withdraw energy simultaneously from both primary and secondary anode circuits.

The nature of the invention may be more clearly understood by reference to the drawing; which illustrates a preferred form of the apparatus. A special form of cathode ray tube is utilized, comprising the usual envelope I having in one end thereof a stem 2 for'holding the cathode. The latter comprises a capsule or cylinder 3 having an opening 5 in the end thereof, and surrounded by a heating coil 8. The interior of the cylinder 3 is preferably coated with a material such as barium or strontium oxide, which emits electrons readily at relatively low temperatures. For high power, however, the cathode may be composed of pure tungsten, thoriated tungsten, or may be of the ordinary filamentary form. Current is supplied through a pair of leads I for heating the cathode.

Positioned at the opposite end of the tube is a disk-shaped anode 8, and a short distance in front of this anode is an auxiliary anode- M. The auxiliary anode is provided with a plurality of openings spaced substantially uniformly adjacent its periphery. Figure 2 illustrates two forms in which these openings may be arranged. 'Ihe openings H are simple circular holes. uniformly spaced. The openings l2 are sectors of circles. Between the openings are bars or spokes l3 and I4 'respectively. The two forms of auxiliary anodes are interchangeable, the sector-shaped openings being, perhaps, preferable. since with this arrangement it is unnecessary that the path of the cathode ray beam be as accurately adjusted as is the case where the round openings are used.

Positioned in front of each of the two anodes is a secondary anode, preferably of annular form, these secondary anodes being indicated by reference characters l5 and I! respectively.

The tube is preferably surrounded by a coil or solenoid l8, which focuses the electrons from the cathode in a manner described in the patent to Philo T. Famsworth, No. 1,986,330, issued January 1, 1935. Two sets of deflecting coils are also provided, the sets of coils being arranged substantially at intervals of 90 from each other around the tube. Coils 28 comprise one of these sets. Only one coil, that indicated by the reference character 2 I, is shown of the second set, the second coil of this set being positioned in front of the plane of the drawing.

The coils 20 and 2| are supplied with polyphase current of relatively low frequency to provide a rotating field. Suitable means for providing this polyphase current are indicated in Figure 3, wherein an electrically driven tuning fork 25 supplies input power to an amplifier 26, whose output circuit contains a resistance 21 and a capacitance 28 in series. The voltages across the elements 21 and 28 are substantially 90 out of phase, and these voltages are fed to the input circuit of amplifiers 30 and 3| respectively. Amplifier 30 supplies current to the coils 20, while amplifier 3| supplies current to the coils 2|.

Reverting to Figure 1, cathode current is supplied from a transformer 32 connected to any suitable source. A lead 33 connects from the center tap on the secondary of the transformer to a generator or other high potential D. C. source 35. The positive terminal of the generator connects through leads 36 and 3'! to a high frequency inductance coil or auto transformer 38,

, the connection preferably, although not necessarily, being to the center of' the coil. Leads 40 and ll connecting to intermediate taps on either side of the connection 31, connect to anodes 8 and I respectively, while the two ends of 'the coil are connected through biasing batteries 43 and 45 to the secondary anodes l and II.

In operation, the electrons liberated from the interior of the cathode are attracted toward the anode structure by the high potential from the generator 35, forming a cathode ray beam. This beam would be normally somewhat divergent, but is reconverged by the longitudinal magnetic field to a focus in the plane of the auxiliary anode l0. At the same time it is deflected by the rotary magnetic field in a closed two-dimensional path, which is preferably circular but which may be somewhat elliptical if the potentials across the elements 21 and 28 are not exactly equal, or if the coils 20 and 2| be not exactly at right angles.

In operation, the beam of cathode rays, swept in a substantially circular path by the rotating field, alternately passes through the openings in the auxiliary anode and is intercepted by the bars or spokes between the openings. During the former period the electron flow from the cathode passes from the anode 8, through the lead 40 and the coil 38, through the leads-31, 33 and 33 back to the cathode, resulting in a voltage drop through a portion of the coil 38. During the period when the beam is intercepted by the auxiliary anode I 0, the electron flow is from the 5 cathode to the auxiliary anode l0, through the lead 4|, and thence back through the coil 38, in the opposite direction, to the lead 31 and thence back to the cathode as before. There is thus set up in the coil 38 an'alternating current whose frequency is equal to the product of the frequency of the driver 25 multiplied by the number of bars or spokes in the auxiliary anode.

Owing to the high potential use between cathode and anode, secondary electrons are liberated I from each of thee-nodes by bombardment. Due to the biasing potential from the batteries 43 and 45, these electrons are collected by the secondary anodes l5 and l'!, the electron flow inthis case being from the secondary anode, through the biasing battery and the end portion of the coil 38, and thence back to the primary anode. This secondary electron fiow is also alternating and in phase with the primary electron flow, so that additional energy is provided in the output circuit by these secondary electrons.

Since all of the portions of the coil 38 are electrically coupled by the inter-linked magnetic field, any desired portion of the coil may be tapped ofi in order to withdraw energy from the circuit. In the present instance, the energy thus tapped off is used to drive an amplifier tube, supplying grid energy for this tube. In the connection shown, one end of the coil 38 connects through a condenser 50 to the grid 5| of the tube 52. The cathode 53 of the tube connects through a lead 55 to the lead 33 and thence to the cathode of the multiplier tube. The anode current of the tube 52 is supplied by the generator 35 through leads 36 and 56, a radio frequency chokecoil 51, and the inductance 58 to the plate 60. The usual grid-leak 6| connects the grid and cathode of the tube, and a blocking condenser 62 is connected between the. filament or cathode 53 and the coil 58.

Coil 58 is preferably tuned by variable condenser 53, the oscillating circuit thus formed acting as a tank-circuit and helping to suppress harmonics which may be generated by the non sinusoidal wave form of the driver. The usual antenna system, comprising either a ground 65 and antenna 66, a doublet antenna, or any other suitable radiator, may be coupled to the coil 58 by means of an inductance 61.

The system thus described has a number of advantages. A tuning fork, especially if supplied with thermostat control, is an exceedingly simple and constant frequency source. Such a fork may readily be made to operate at from two to four thousand cycles. By careful construction, 00 the auxiliary anode may-be made to yield multiplying factors as high as one thousand. This permits frequencies as high as 10,000 kilocycles to be generated directly, all the amplification, except that of the last stagejbeing at easily handled audio frequencies.

I claim:

1. A high frequency generator comprising means for establishing a rotating field of relatively low frequency, means for directing a beam of cathode rays through said field, whereby said beam is deflected in a closed two-dimensional path, a solid anode positioned to receive the dcfiected beam, a foraminated anode having alternate bars positioned to intercept said beam and 15 amass:

spaces through which the beam may pass to said first mentioned anode to deliver charges to said anodes alternately, secondary anodes positioned to receive electrons liberated from said primary anodes by bombardment, an output circuit and means for additively delivering the energy received by said primary and secondary anodes to said output circuit.

2. A high frequency generator comprising means for establishing a rotating fleld oi relatively low frequency, means for directing a beam of cathode rays through said field, whereby said beam is deflected in a closed two-dimensional path, a solid anode positioned to receive the deflected beam. an anode having alternate bars positioned to intercept said beam and spaces through which the beam may pass to said first mentioned anode to deliver charges to said anodes alternately, secondary anodes positioned to neceive electrons liberated from said primary anodes by bombardment, and an output transformer having a plurality of taps connecting respectively to said anodes, said primary anodes 10 being connected to taps intermediate those to which said secondary anodes are connected.

R.ALPH M. HEINTZ. 

